test/examples: various improvements

[G4Vi]

• Fix broken module kitchensink.c
• Add reactor module and example
• Add component reactor and example

• fix component build by pinning cli tool versions

• An example of running the reactor MODULE example: https://github.com/dylibso/observe-sdk/blob/test-examples-improvements/.github/workflows/ci.yml#L110-L113
• An example of running the reactor COMPONENT example: https://github.com/dylibso/observe-sdk/blob/test-examples-improvements/justfile#L27-L33